She told the BBC's Andrew Marr today that she had been screamed and shouted at, and activists had sung: "We'll be watching you" at her as a form of intimidation.

"A man would not have been treated like this," she said. "It's a toxic political culture."

In an interview with The Times yesterday she said: "Antisemitism is tolerated within the Labour Party. That Ken Livingstone is still in the Labour Party I find inexplicable."

A party spokesman told The Sunday Times: "We do not comment on leaked documents. The NEC’s disputes panel operates in line with our party’s procedures."

A previous version of this article reported that Mike Sivier had said it was "not a big problem" if Jews were taken off a list of Holocaust survivors. In fact, Mr Sivier was referring to anti-Semitism on the left as not being a "big problem". The article also reported that he had said he did not know whether thousands or millions of people died in the Holocaust. He says that this comment referred to him not knowing why the SWP had referred to "thousands" of Holocaust victims in a pamphlet. It also previously described Mr Sivier as a "Holocaust denier". He says he is not; we are happy to put this on record. This clarification has been published following an upheld ruling by the Independent Press Standards Organisation.